Basic aluminosilicates

Our synthetic routes to ZK4 were modifications of those described by Kerr (21). An amorphous, basic aluminosilicate gel containing tetramethylammonlum (TMA) Ion was heated at 100°C to promote formation of ZK4 crystals. Preparation of the gel Involved the vigorous mixing at room temperature of one component acting as a source of sodium and alumina, with another component acting as a source of TMA and silica. The alumina used was sodium... 

In basic medium, negative A1 species appear and condense with the remaining silicate entities, as to yield an Al-rich aluminosilicate gel. A few Al-richer nuclei can then form and yield a small amount of Al-richer ZSM-5 particles at the end of the process. 

Kaolin Minerals. The 1 1 structures include a group of aluminosilicate minerals which are termed collectively the kaolin minerals specifically these are kaolinite, dickite, nacrite, and halloysite. The basic 1 1 layer for all of these minerals has the composition AlgSigOj-fOHJj, there is a small amount of substitution of iron for aluminum, ana fluoride for hydroxyl ion. All, except halloysite, are normally anhydrous and do not expand (as do the smectites) upon exposure to water and most organic molecules. As a result, they generally have a rather small surface area, on the order of 10 nr... 

The concentrations of dissolved species in natnral waters depend ultimately on the dissolution of basic rocks-carbonates, silicates and aluminosilicates-induced by the action of weak acids in the water derived from dissolved gases-e.g. H2CO3 derived from CO2. Anions produced in acid-base reactions balance cations produced in dissolution reactions. The charge balance is ... 

Because the clays have a basic layered structure of aluminosilicate sheets the expectation was a platy habit. The creation of tubular forms was studied by Bates (1959). He postulated that the curved forms, observed by electron microscopic investigation of halloysite and chrysotile, originated through the relief of strain between sheets of unequal dimensions. 

Most of the adsorbents used in the adsorption process are also useful to catalysis, because they can act as solid catalysts or their supports. The basic function of catalyst supports, usually porous adsorbents, is to keep the catalytically active phase in a highly dispersed state. It is obvious that the methods of preparation and characterization of adsorbents and catalysts are very similar or identical. The physical structure of catalysts is investigated by means of both adsorption methods and various instrumental techniques derived for estimating their porosity and surface area. Factors such as surface area, distribution of pore volumes, pore sizes, stability, and mechanical properties of materials used are also very important in both processes—adsorption and catalysis. Activated carbons, silica, and alumina species as well as natural amorphous aluminosilicates and zeolites are widely used as either catalyst supports or heterogeneous catalysts. From the above, the following conclusions can be easily drawn (Dabrowski, 2001) ... 

Li2B407 or LiBOi or Na2B407 Ft, graphite Au-Ft alloy. Au-Rh-Ft alloy Individual or mixed borates are used to dissolve aluminosilicates, carbonates, and samples with high concentrations of basic oxides. B407 is called tetraborate and B02 is metaborate. 

An alternative hypothesis, developed from studies of the synthesis of Linde A zeolite carried out by Kerr (5) and Ciric (6), pointed to growth occurring from solution. The gel was believed to be at least partially dissolved in solution, forming active aluminosilicate species as well as silicate and aluminate ions. These species linked to form the basic building blocks of the zeolite structure and returned to the solid phase. Aiello et al. (7) followed the synthesis from a highly alkaline clear aluminosilicate solution by electron microscopy, electron diffraction, and x-ray diffraction. These authors observed the formation of thin plates (lamellae) of amorphous aluminosilicates prior to actual crystal formation. 

The Q notation used above is not sufficient to describe the basic building units in a/uminosilicates. While in framework silicates the environment of each silicon atom is always Q4(4Si), in framework aluminosilicates there are five possibilities described by the formula Q4[nAl, (4 — n)Si], where n = 0,1, 2, 3, or 4. We shall for simplicity denote these five basic units as Si(nAl)... 

The phenomenon of increased hardness occurs principally in minerals of sheet and chain structures, which link together through the cations (silicates and aluminosilicates, as well as hydrated sheet minerals, such as glauconite, melilite and gypsum—M ranging from 0 to about 1.25), and also in minerals of skeletal structures (borates, phosphates, sulphates, nitrates, carbonates, such as calcite, dolomite and others—Ah from 0 to about 1.15). For this reason, the hardness analysis of minerals with weak bonds demands consideration of the fact that just as the basic crystallo-chemical factors, so is hardness influenced by the form of domains (component parts of structures) in all anisodesmic minerals of chain, sheet or skeletal structure. Depending on the form of domain (and also according... 

The primary minerals of igneous rocks are all mildly basic compounds. When they react in excess with acids such as HC1 and CO2, they produce neutral or mildly alkaline solutions plus a set of altered aluminosilicate and carbonate reaction products. It is improbable that ocean water has changed through time from a solution approximately in equilibrium with these reaction products, which are clay minerals and carbonates. 

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